ellenwst-
I highly suggest that you talk to your son about the situation....and definitely look into other possibilities for his behavior. If it seems as though it is the Adderall, I would definitely have him switch meds ASAP. I have talked to a number of people who absolutely hate that their parents had them take meds because of the effects it had on their lives. (This is what they say after they have grown older and stopped meds because of how they felt on them.)
Good luck and keep us posted!
OMG! This really hits home. My son started Adderall XR (20mg) about 10 months ago and although he gets straight As and plays soccer, is not involved with drugs or alcohol and generally a straight-laced wonderful kid, he never has friends over, never goes to parties, never socializes and I worry myself sick about it and very sad. It hurts.
It's possibly the Adderall I guess. This is the first post I've seen about something like this.Every person responds differently to meds.....For some, they cause anti-social behavior or a zombie effect. If you feel that your meds are inhibiting your social life or if they are bothering you, then perhaps you do want to try a different med.
I personally take adderall and adderall xr....I have for a few years now and, fortunately, I haven't experienced any side effects. My social life is great, appetite is good, etc...Although, I don't medicate myself to the point where I would become zombied--I'm difinitely still AD/HD 
Don't know if this will help at all, but good luck and keep us posted!